When autoclaving sample tubes containing growth media, the current state of the art is to use a number of different trays to achieve the final result. In some cases, up to three different trays are used to produce a sample tube with slanted growth media. Since the autoclave is a high heat and pressure device, the tray must be capable of withstanding both high heat and high pressure. Typically, a metal tray is used in autoclaves because of its tolerance to high temperature and overall ruggedness when being handled. However, the metal tray has several disadvantages, including longer heating and cooling cycles, imprecision of fit for the sample tubes within the holes of the tray, limited size, and weight. These last two disadvantages are critical because the heavier weight limits the size of the tray, which in turn limits the throughput of a labor intensive production line and, if used to ship the sample tubes, increases shipping costs. To compensate for these disadvantages, a manufacturer must perform all of the production steps other than autoclaving using a lighter weight tray with a greater tube capacity than the metal tray. But by adding another tray to the process, additional steps of removing the tubes from one tray (called detraying) and placing the tubes in metal trays for autoclaving become necessary. The tubes must then be detrayed again for placement into shipping trays, which may or may not be the same trays used for handling prior to autoclaving. Improvements are therefore desired.
The prior art sample tube shipping or packaging trays 70, as shown in FIG. 4, do not have well bottoms that support the sample tubes 150 from beneath. This creates potential problems when filled trays 70 are stacked one on top of another or when the filled trays 70 are placed on an uneven surface. The tray 70 does not have a means for securely holding the sample tubes 150 even when the trays are upright. This loose fit is problematic because the sample tubes 150 may be damaged. The trays 70 merely have a well opening 80 large enough to accommodate sample tubes 150 and the sample tubes 150 have a height taller than the legs 82 of the trays 70. Since the sample tubes 150 are taller than the trays and the well openings 80 are loose, picking up the trays 70 to move them causes the sample tubes 75 to slide down in the well openings 80 up to their caps 72. In addition, when the trays 70 are placed on an uneven surface, the sample tubes 150 may slide upwardly in the well opening or down to conform to the uneven surface. The loose fit of the sample tubes 150 in the tray 70 make the tray unsuitable for producing slanted growth media in an autoclave or inspissator. Completely enclosing the sample tubes 150 insulates the sample tube from the sterilizing steam and the cooling air/water of the autoclave cycle possibly resulting in incomplete sterilization, as well as inhibiting cooling.